fsmonitor: fix hashmap memory leak in fsmonitor_run_daemon

The `state.cookies` hashmap is initialized during daemon startup but
never freed during cleanup in the `done:` label of
fsmonitor_run_daemon().  The cookie entries also have names allocated
via strbuf_detach() that must be freed individually.

Iterate the hashmap to free each cookie name, then call
hashmap_clear_and_free() to release the entries and table.

Signed-off-by: Paul Tarjan <github@paulisageek.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: ptarjan

builtin/fsmonitor--daemon.c

@@ -1404,6 +1404,15 @@ static int fsmonitor_run_daemon(void)
 done:
 	pthread_cond_destroy(&state.cookies_cond);
 	pthread_mutex_destroy(&state.main_lock);
+	{
+		struct hashmap_iter iter;
+		struct fsmonitor_cookie_item *cookie;
+
+		hashmap_for_each_entry(&state.cookies, &iter, cookie, entry)
+			free(cookie->name);
+		hashmap_clear_and_free(&state.cookies,
+				       struct fsmonitor_cookie_item, entry);
+	}
 	fsm_listen__dtor(&state);
 	fsm_health__dtor(&state);